# 728

## 728 is an even composite number composed of three prime numbers multiplied together.

What does the number 728 look like?

This visualization shows the relationship between its 3 prime factors (large circles) and 16 divisors.

728 is an even composite number. It is composed of three distinct prime numbers multiplied together. It has a total of sixteen divisors.

## Prime factorization of 728:

### 23 × 7 × 13

(2 × 2 × 2 × 7 × 13)

See below for interesting mathematical facts about the number 728 from the Numbermatics database.

### Names of 728

• Cardinal: 728 can be written as Seven hundred twenty-eight.

### Scientific notation

• Scientific notation: 7.28 × 102

### Factors of 728

• Number of distinct prime factors ω(n): 3
• Total number of prime factors Ω(n): 5
• Sum of prime factors: 22

### Divisors of 728

• Number of divisors d(n): 16
• Complete list of divisors:
• Sum of all divisors σ(n): 1680
• Sum of proper divisors (its aliquot sum) s(n): 952
• 728 is an abundant number, because the sum of its proper divisors (952) is greater than itself. Its abundance is 224

### Bases of 728

• Binary: 10110110002
• Base-36: K8

### Squares and roots of 728

• 728 squared (7282) is 529984
• 728 cubed (7283) is 385828352
• The square root of 728 is 26.9814751265
• The cube root of 728 is 8.9958828905

### Scales and comparisons

How big is 728?
• 728 seconds is equal to 12 minutes, 8 seconds.
• To count from 1 to 728 would take you about six minutes.

This is a very rough estimate, based on a speaking rate of half a second every third order of magnitude. If you speak quickly, you could probably say any randomly-chosen number between one and a thousand in around half a second. Very big numbers obviously take longer to say, so we add half a second for every extra x1000. (We do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!)

• A cube with a volume of 728 cubic inches would be around 0.7 feet tall.

### Recreational maths with 728

• 728 backwards is 827
• The number of decimal digits it has is: 3
• The sum of 728's digits is 17
• More coming soon!